<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>3CSS常用值</title>
    <style>
        h1{
            color: red;
            color: rgb(255,0,0);
            color: rgb(0,255,0);
            color: rgb(0,0,255);
            color: #ff0000;
            color: #00ff00;
            color: #0F0;
            color: #000000;
            color: #000;
            /*不透明度 alpha*/
            color: rgba(0,0,255,0.8);
            color: rgba(0,0,255,0.5);
            color: rgba(0,0,255,0.3);
            color: rgba(0,0,255,0);
            color: rgba(0,0,255,1);
        }
        .d1{
            background-image: url(img/mr.png);
            width: 50px;
            height: 100px;
            background-size: 50px 100px;
            background-color: cyan;
        }
        .d2{
            width: 300px;
            height: 300px;
            border: 5px solid #f00;
            background-image: url(img/mr.png);
            background-repeat: no-repeat;
            background-position: 0 0;
            background-position: -50px 0;
            background-position: 0 -50px;
            background-position: 50px -50px;
        }
        .d4{
            background-image: url(img/computer1.png);
            width: 611px;
            height: 376px;
            background-repeat: no-repeat;
            background-color: #e8e8e8;
            background-size: 318px 319px;
            background-position: 90% 60%;
        }
    </style>
</head>
<body>
<h1>测试颜色</h1>
<div class="d1"></div>
<div class="d2"></div>
<div class="d4"></div>

</body>
</html>